Re: [dpdk-dev] Is there any example application to used DPDK packet distributor library?

[Bruce Richardson <bruce.richardson@intel.com>]

On Wed, Sep 30, 2015 at 08:41:04PM +0900, 최익성 wrote:
>  Dear Bruce Richardson and DPDK experts.
>  
> Thank you very much for your precious answer.
>  
> I found it. It seems very short and simple.
>  
> Thank you very much.
>  
> I have another question.
>  
> I don't know how the following steps work from new_tag to match variables.
>  
> /* in dpdk library. ~/dpdk-?.?.?/lib/librte_distributor/rte_distributor.c */
> /* process a set of packets to distribute them to workers */
> rte_distributor_process(struct rte_distributor *d, struct rte_mbuf **mbufs, unsigned num_mbufs)
> {
> ...
>      new_tag = next_mb->hash.usr;  /* flow ID hash.usr is set by NIC */
>  
>      for (i = 0; i < d->num_workers; i++)
>           match |= (!(d->in_flight_tags[i] ^ new_tag) << i);
>  
>      /* Only turned-on bits are considered as match */
>      match &= d->in_flight_bitmask;
>  
>      unsigned worker = __builtin_ctzl(match);
> ...
> }
>  
> I will appreciate if you let me know the steps.

We build up a bitmask for each worker, where the bit is set of the new_tag
matches the inflight tag for the worker. We then find the matching worker, if
any using count-training-zeros (ctz) operation.

/Bruce

>  
> Thank you very much.
>  
> Sincerely Yours,
>  
> Ick-Sung Choi.
>  
>  
> -----Original Message-----
> From: "Bruce Richardson"<bruce.richardson@intel.com> 
> To: "최익성"<pnk003@naver.com>; 
> Cc: <dev@dpdk.org>; 
> Sent: 2015-09-30 (수) 19:56:28
> Subject: Re: [dpdk-dev] Is there any example application to used DPDK packet distributor library?
>  
> On Wed, Sep 30, 2015 at 02:45:20PM +0900, 최익성 wrote:
> > Dear DPDK experts.
> >  
> > I am Ick-Sung Choi living in South Korea.
> >  
> > I have a question about DPDK에 packet distributor library.
> >  
> > Is there any example application to used DPDK packet distributor library?
> >  
> > I am trying to experiment simple function using DPDK packet distributor library.
> >  
> > If I can study an example application of DPDK packet distributor library, it would be very helpful for my experiment.
> >  
> > I will appreciate if I can be given any example applications, advice, and information.
> >  
> > Thank you very much.
> >  
> > Sincerely Yours,
> >  
> > Ick-Sung Choi.
> >  
> Hi,
> 
> there is a "distributor" example app in the examples directory.
> 
> /Bruce
>